In the 1920s, engagement rings featuring diamond halos became popular.

According to WP Diamonds, engagement rings with geometric shapes and sharp lines were popular in the 1920s, coinciding with the height of the Art Deco period. Emerald–cut and Asscher diamonds were especially common, and more extravagant rings were accentuated with diamond halos.

Engagement rings in the 1930s featured bands shaped like ribbons.

Engagement rings in the 1930s were “trying to evolve” from the Art Deco period, according to WP Diamonds’ infographic. Single diamonds were often used as the centrepiece on bands shaped like ribbons or bows.

Emerald-cut diamonds continued to be popular in the ’70s.

During this decade, brides also began to match their engagement rings to their wedding bands, many of which were yellow- and rose-gold.

Colourful diamonds and gemstones were huge in the 1980s.

Oli Scarff/Getty ImagesEmeralds, rubies, and sapphires are popular examples of colourful gemstones.

Round-cut diamonds and yellow-gold bands were still extremely popular in the ’80s, but Princess Diana’s engagement ring from Prince Charles, which featured a sapphire gemstone, changed the nuptials industry.

The royal ring was so popular that many replicas were made, according to WP Diamonds’ infographic.

Engagement rings in the 1990s were greatly influenced by the rise of grunge.

Stephen Shugerman/Getty ImagesAlso known as the football cut, marquise cuts became popular this decade.

With the rise of grunge in the 1990s, rings became bolder and sharper. Marquise-cut diamonds were particularly fashionable, and yellow-gold bands took a backseat to bands made of white gold and platinum.

Princess-cut diamonds dominated engagement ring trends in the early 2000s.

Ethan Miller/Getty ImagesEngagement rings of the early 2000s were chic.

Many couples in the 2000s opted for engagement rings with large diamonds or stones. Taking inspiration from the ’60s, the princess cut also came back into fashion.

By the early 2010s, cushion-cut diamonds became the most popular choice for couples.

According to WP Diamonds, the classic cushion cut is still popular today.

Currently, oval diamonds are all the rage.

Skinny bands and large oval diamonds are in style, according to WP Diamonds. Usually set vertically – or, on occasion, horizontally – oval diamonds let couples play around with the appearance of their engagement rings. Celebrities like Julianne Hough and, more recently, Hailey Baldwin, are also fans of oval engagement rings.

Another huge trend in 2018 is having a custom-designed ring, as brides aim to better showcase their individual personalities.

In the past century, the most popular ring style has been a gold band with a solitaire stone.

Scott Barbour/Getty ImagesThis minimalist design is timeless.

Speaking to INSIDER, the president of WP Diamonds, Andrew Brown, said the most popular engagement ring style in the last 100 years is actually pretty simple: A “round solitaire diamond, around one carat, set on a simple yellow-gold band.”

According to Brown, there will always be innovation in the diamond industry but trends often “revert to the classics.”

So, what will come next? Brown thinks that round diamonds will “remain the most popular shape” while oval and cushion cuts will “continue in their rise.” The WP Diamonds president also expects other trends to go out of style, like the princess cut popularised in the early 2000s.

Unfortunately for those who love colourful stones, Brown said that we can also expect to see a “decline in production of coloured diamonds due to supply constraints.”